1. Field of the Invention
This invention relates to a pipe rerounding apparatus having a pair of opposing jaws for compressing pipe that is outside of ovality specifications.
2. Description of Prior Art
There are two primary methods that are widely used to correct the ovality of round plastic pipe: (1) rolling rerounding wheels; and (2) hydraulic or mechanical 3-point bending tools. Neither of these inventions is directed specifically to rerounding small sections of pipe. The former is designed for long sections of pipe (typically hundreds of feet) and the latter deals primarily with the curvature at the end of a coil of pipe, rather than with the oval cross-section.
Rolling rerounding wheels, such as the commercially available LINE TAMER™ supplied by MacElroy, Inc. or the PE Pipe Rerounder supplied by PLCS Inc., are designed to reround pipe sections typically hundreds of feet long as the pipe is pulled through a set of vertical, contoured rollers. The MacElroy, Inc. device is mounted on a separate trailer that is towed behind a coiled pipe dispensing trailer, costs approximately US$15,000, and weighs over 1,000 pounds. The PLCS device is mounted on the back of a coiled pipe trailer, costs approximately US$8,000, and weighs over 100 pounds. Both of these devices consist of a pair of tapered rollers that are slightly hour-glass shaped and compress the pipe perpendicular to its long axis. However, the rollers contact the pipe at only a single point. To effect a rerounding of a significant length of pipe, the pipe is pulled through the roller wheels. This pulling requires several hundred to over 1,000 pounds of force, making it impossible to reround pipe manually. These tools cannot be used once the pipe has been placed in a trench because both devices require the pipe be pulled through the rollers, usually as it is dispensed from a coiled pipe dispensing trailer.
A second technique for dealing with coiled pipe locally is a 3 point bending tool. One commercially available example of such a tool is marketed as the CROCOPLAST™. This device bends the pipe at 3 points along the longitudinal axis, the intent being to remove the curvature from the end of the pipe. This tool is not designed to reround the pipe's oval cross-section and it does not effect such a rerounding.